The present invention relates to a method and apparatus for well logging and well control.
In order to maintain well control it is necessary for a well to be filled with a fluid. Such fluids are usually mud mixtures and the density of the mud is usually controllable to suit particular conditions within a well, Such fluid is usually continuously pumped down a drill pipe and up the borehole between the pipe and the side of the borehole and the drill pipe.
The type of mud, in particular the density of mud which flows within the borehole may be carefully controlled to, for example, prevent escape of gas. For some wells the mud density may require to be much higher than for others. During the time that the well is in operation it may be necessary to change the density of the mud mixture to, for example, cope with additional gas pressure within the well.
In such circumstances, logging of the well becomes dangerous because circulation of fluid/mud is required and this is not achievable without drilipipe in the hole. Thus, many wells are not logged and because of this the full potential of the wells is not achieved.
Additionally, in a well which has a large wash-out at a depth below the surface, the logging cannot proceed past this section.
It is an object of the present invention to provide a method and apparatus for both well logging and simultaneous well control.
The present invention provides a method for well logging and well control comprising of a well:
a) inserting a well logging tool into the well,
b) transporting said well logging tool down to a desired position in said well inside drillpipe and out into openhole,
c) transporting said well logging tool upwardly in said well and logging data from said well as said tool is transported by wireline or drillpipe,
d) continuing to supply fluid flow in said well, whilst said logging of data is taking place said fluid flowing through said data logging tool or around the outside if wireline conveyed,
Preferably said method includes the step of e) increasing the pressure of the fluid flow in said well to energise said data logging tool to create a path through said tool for said fluid.
The present invention also provides apparatus for well logging and control said apparatus comprising fluid pump means for pumping fluid into a well, a well logging tool situated within said well, said well logging tool comprising fluid valve contact means for allowing fluid to pass through said logging tool to allow fluid contact to be maintained in said well.
The present invention may also comprise drill pipe means situated in said well, and drill pipe means extending over washout portions of said well.
In a specific embodiment the apparatus may include drill bit means said drill bit means comprising means for enabling said logging tool to protrude through said drill bit to enable logging to be completed without withdrawal of said drill bit means, said logging operation also enabling well control. And use pumpdown and reverse circulating technique to deploy and recover the logging tools.